cBN is a high-hardness substance after diamond, and a cBN sintered body is used in various cutting tools, wear-resistant components, impact-resistant components and the like. A sintered body having a high content of cBN is generally used particularly for cutting of a cast iron/sintered alloy, and depending on processing conditions, the particle size of a cBN particle and the composition of a binder phase are optimized. Generally, if the content is fixed, toughness is enhanced as the cBN particles included in the sintered body become coarser. On the other hand, strength decreases because the binder phase becomes thicker. The relationship between the thickness of the binder phase and the strength is described in PTL 1. PTL 2 describes an example in which defects and microscopic cracks are eliminated in order to enhance chipping resistance and wear resistance of cBN particles themselves.